Clutch



April 13, 1937- w. J. PEARMAIN 2,077,154

CLUTCH Filed 0G13. 50, 1935 2 Sheets-Sheet J J J2 vPatented Apr. 13, 1937 CLUTCH William J. Pearmain, Racine, Wis., assigner to Twin Disc Clutch Company, Racine, Wis., a corporation oi.' Wisconsin Application October `30, 1935, Serial No. 47,453

l Claims.

My invention relates toclutches and is concerned more particularly with a clutch in which transmission of power is effected between itary parts through mechanism which is normally in driving engagement.

One object of my invention is to devise a clutch in which the unloading mechanism includes parts mounted directly on the iioating plate and iiywheel, or other rotary part, respectively, avoiding the usual necessity for employing a coverplate or the like, and thereby materially simplifying the clutch structure.

A further object is to provide a clutch in which the unloading mechanism is so constructed and arranged that its release position is maintained by the extending action of the loading springs.

A further object is to devise a clutch in which the principal element of the unloading mechanism is a bell crank lever pivoted on the oating plate and one arm of which bears against the other gripping member of the clutch whereby the oating plate is shifted to release position, the

. arm being rocked to an over center position to enable the loading springs to maintain .the clutch in disengagement without additional holding means.

A further object is to provide a clutch as above indicated in which the driving elements are secured to a ring that is capable of being attached to a iiywheel or other rotary part, the elements engaging the oating plate and serving as. fulcrums for the releasing movement of the unloading mechanism.

These and further objects of my invention will be set forth in the following specification, reference being had to the accompanying drawings, and the novel means by which said objects are effectuated will be denitely pointed out in the claims. y

In the drawings:

Figure 1 is a sectional elevation of my improved' Fig. 5 is an end'elevation of the clutch. asv

. viewed in the direction of the arrow 5 in Flg. 1.

Fig. 6 is a fragmentary, sectional view, corre-v sponding to that illustrated in Fig. 3, but illustrating a modiiied type of unloading mechanism,l the clutch being shown in disengaged position.

Referring to Fig. 1, the -numerals I and II designate, respectively.a flywheel and a shaft, which', forpurpose of illustration may lbe regarded generally as the driving and driven memers of the clutch. One end of the shaft is splined 10 as at I2 to receive a hub I3 which is thereby compelled to partake of the rotary motion of the shaft, but is adapted for axial movement therealong. The hub has secured thereto a. friction plate Il which is provided on opposite sides, as by riveting or the like, with iacing's of frictional material I5.

The left facing, as viewed in Fig. 1, is intended` to engage with the face I6 of the flywheel, while the other facing engagesvwith the opposed side or face of a floating plate Il. Around its periphery, the plate I1 is provided with a plurality oi.' pairs of ears I8, each of which is provided on its inner face with a boss I8, and between the inner faces of each pair of these bosses extends `the limbs of a fork I9 that is' provided with a stud y end 20 fastened in a ring 2| that is'secured to the flywheel by means of bolts 22 (see Fig'. 5).

necessary driving engagement between the y- .Wheel and the oating plate, while allowing for axial movement of the floating plate relative to the ilywheel (see'Flg. 2). f

A plurality of v screws 23 are circumferentially. 35 spaced in and around the ring 2I and their shanks pass freely through apertures 2l provided in the l oating plate to receive on the extremities re- -taining nuts 2B and cup washers 25. A loading spring 2l encircles each of the screws 23, with one end thereof bearing against the washer 25 and the opposite end against a washer 28 which encircles a centering boss 29 that may be formed by suitably recessing the external face vof the oating plate.' 'Ihe normalaction of the springs 2l 45 isv to apply the necessary pressure to the iloating other material whereby the springs are 'protected from what would otherwise be directly conducted" f heat from the oating plate. The screws 23 only serve as a locating element' for the-loadingy I springs and do not serve to'transmit anyof ythe'fv driving force from the flywheel to the iioating plate,.the latter action being a function of the forks I3.

One o1' the most important featur'es of my improved clutch resides in the novel construction of 5 the unloading mechanism and this portion of the device will now be described. A pin 3U is bridged between and freely rotatable in each pair of ears I 8 and the hub of a bell crank lever 3| is mounted on that portion of the pin between the ears. 10 An adjusting screw 32 is threaded. through the lever hub and passes freely through an aperture provided in the pin 30 so that the lever is journaled in the ears I8, rather than upon the pin 30.

The inner extremity ofthe screw 32 bears against the inner fiat end of a cylindrical block 33 that is slidable in a stub arm 34 whose ,open end faces outwardly toward the fork I9. The outer end of theblock 33 is preferably rounded for engagement with the surface of a roller 35 that is pivoted on a pin 36 bridged between the limbs of the fork I9. Endwise movement of the blockB 33 is limited by a cotter pin 31 that passes through the stub arm 34 and engages the base of a slot 38 formed by milling one side of the block 33 (see Fig. 4). The purpose of the adjusting screw 32 is to vary the length of one of the lever arms, as formed by the stub arm 34 and block 33, in order to compensate for the wear of the friction facings I5. The adjusted position 'of the screw 32 may be locked by a nut 39.

The other arm 40 of the bell crank lever extends is pivotally connected to a sleeve 44 that is freely 40 slidable along theshaft I I. It will be understood that the construction of the bell crank lever, as l above described, is identical for all of the levers of the clutch Vand that as many of thesebell crank levers may be employed as operating con- 45 ditions require. The inner race of a ball bearing 45 is mounted upon the sleeve 44 and the outer race of this bearing is closely tted in a collar 46 that is provided at one end with a flange 41 for retaining the bearing 45 against endwise move- 50 ment in one direction. Movement of the bearing in the opposite direction is prevented by a retaining ring 48. The collar 46 is provided with the usual trunnions 49 that are intended to engage With a suitable shifting fork (not shown). By reason of the foregoing constructiomit' is evident ythat the collar 46 will shift the sleeve 44 along the shaft II, but will not partake of the rotary movement of the sleeve.

As shown in Fig. 3, the' various members-of the clutch are 'in driving position, owing to the pressure furnished by the springs 21 which grip the friction plate I4 between the flywheel I0 and the floating plate I1. To release the clutch and thus interrupt the flow of powerfrom the flywheel to the shaft, the sleeve 44 is moved along the shaft toward the left, as viewed in Fig. 1, thus causing a movement of the lever arms 40 `toward the floating plate. During this movement, the rounded ends of the blocks 33 bear against the rollers 35 as fulcrums and thus shift the .floating ple toward the right against the extending action of the springs 21. This rocking action of the bell crank levers is continued until the blocks 33 reach the over-center position, relative to the center ofthe 35, 5S

Y of the levers.

stood that, owing to the free mounting-oi' the."

friction plate I4, it will accommodate itself endwise of the shaft II so that it will be substan-..

tially freed of engagement with the flywheel I0. As the' facings I5 wear, the short armof each bell crank lever can be literally lengthened by adjusting the block 33 outwardly in order to achieve the required contact thereof with the rollers 35 and so retain the full releasing capacity Preferably, and as clearly indicated in Figs. 1 and 3, the distance of-the axis of each pin 30 radially from the shaft I I is greater than th'e similar distance of each pin 36, thus providing for a. quick release of the bell crank levers when moved toward the right by the sleeve 44, this movement obviously releasing the floating plate I1 so that it may be shifted into driving position by the springs 21.

The modification-illustrated in Fig. 6 differs from that heretofore described in that no provision is made for adjustment. In this arrangement, driving pins 5I, corresponding to the driving forks I9 have their outer ends rounded as at 52 for engagement with a roller 53-that is pivoted in a bifurcated arm 54 of a. bell crank lever 55, the arm serving the same purpose as the stub arm 34 and the block 33, and the other arm 56 extending inwardly of the clutch for connection with a sleeve similar to the sleeve 44. The action of this clutch and its unloading mechanism is identical with that heretofore described.

Moreover, since the principal elements of `the unloading mechanism are mounted on the iioating plate, it is possible to omit the usual cover plate, thereby enabling the clutch springs 21 to be freely exposed to the surrounding airso that they are maintained in a cooler condition and hence are not as likely to acquire a permanent set due to frictional heat. y

I claim:

1. In a clutch, the combination with a friction plate attachable to a rotary part, a 'pair of gripping members connectble to a second rotary part and disposed on opposite sides of the plate, one of said members having projections on one face thereof and the other of said members constituting a floating plate movable axially relative to the other member, and springs for maintaining the driving engagement of the members and friction plate, of unloading mechanism for releasing said engagement comprising bell crank levers rockably mounted on the floating plate, and means for actuating one arm of each lever, the other arms fulcruming against -the associated projections to thereby disengagethe floating plate, the radius of each lever pivot being greater than the radius of the associated projection thereby' providing for a quick releasing movement i ofthe levers to free the floating plate for return to gripping position.

2. In a clutch, the combination with a friction plate attachable/ to a rotary part, a pair of gripping members connectble to a second rotary part and disposed on opposite sides of the plate, one of the members having a plurality of spaced pro- J'ections circumferentially arranged around the` t face thereof and the other member constituting a floating plate movable axially relative to the other member, and springs for maintaining the driving engagement of the members and friction plate, of unloading mechanism for releasing said engagement comprising bell crank levers rockably mounted on the floating plate, means for actuating one arm of each lever, the other lever arms fulcruming against the associated projections to thereby disengage the floating plate and moving to an over-center position relative to the cooperating projections to lock th'e clutch in disengaged position, and means formed on the floating plate for limiting the releasing movement of said first named lever, arms to maintain said over-center position. I

3. In a clutch, the combination with a friction plate attachable to a rotary part, a pair of gripping members connectible to a second rotary part and disposed on opposite sides of the plate, one of said members constituting a floating plate movable axially relative to the other .memben pins mounted in said other member and having driving engagement with the iloating plate, and springs for maintaining the driving engagement of the members and friction plate, of unloading mechanism for releasing said engagement comprising 'bell crank levers rockably mounted on the floating plate, and means for actuating one arm of each lever, the other arms .fulcrumingl against the associated'plns to therebydisengage the floating plate and moving to an over-center position relative to the cooperating pins to lock the clutch in disengaged position, the radius of each lever pivot being greater than the radius of the associated pin thereby providing for a quick releasing movement of the levers to free the floating plate for return to gripping position.

4. In a clutch, the combination with a friction plate attachable to a rotarypart, a pair of gripping members connectible to a second rotary partA and disposed onopposite sides of the plate, one of the members having a plurality of spaced projections circumferentially arranged around the face thereof and the other member constituting a floating plate movable axially relative to the other member, and springs for maintaining the driving engagement of the members and friction plate, of unloading mechanism for releasing said engagement comprising bell crank levers rockably mounted on the floating plate, means for actuating one arm of each lever, the other lever arms fulcruming against the associated projections to thereby disengage the floating plate and moving to an over-center position relative to theA cooperating projections to lock the clutch in disengaged position, and means formed on the floating plate for limiting the releasing movement of said first-named lever arms to maintain said over-center position, the radius of each lever pivot being greater than the radius of the associated projection thereby providing for a quickf releasing movement of the levers to free the floating plate for return to gripping position.

5. In a clutch, the combination with a friction plate attachable to a rotary part and freely movable axially relative thereto, a pair of gripvping members connectible Ato a second` rotaryY part and disposed on opposite sides of the plate, one of the members having projections on one face thereof and secured vagainstaxial movementl and the other of the members constituting a floating plate movable axially relative to the other member, and springs for maintaining the driving engagement of the members and friction plate, of unloading mechanism\ for releasing said engagement comprising pins journaled on the floating plate, a bell crank lever mounted on each pin, means for actuating one arm of each lever, the other arm having an adjustable block adapted to fulcrum against the associated projection to thereby disengage the floating plate and the ends of the fulcruming lever arms being shifted to an over-center position with respect to the cooperating projections to therebyy lock thegclutch in disengaged position,I and means for adjusting the position of each block as the clutch wears, said adjusting means passing through the pins to secure the levers thereto.

6. In a clutch, the combination with a friction plate attachable to a rotary part, a pairof gripping` members connectible to a second rotary part and disposed on opposite sides of the plate, one of the members constituting a floating plate movable axially relative to the other member, projections formed on the other member having driving engagement with the floating plate, and

springs for maintaining the driving engagement of the members and friction plate, of unloading mechanism for releasing said. engagement comprising pins journaled on the floating plate, av

bell crank lever mounted on each pin, means for actuating one arm of each lever, the other arm `having an adjustable block adapted to fulcrum against the associated projection to thereby disengage the floating'plate and moving to an overcenterp'o'sition relative to the co-acting projection to locky the clutch in disengaged position,

the radius of each pin being greater than the radius of the associated projection to thereby provide for a quick releasing movement of the levers to free the floating plate for return to gripping position, and means for adjustingl the p osition of each block as the clutch wears, said adjusting means passing through the pins to secure the levers thereto.

7. In a clutch, the combination with a friction plate attachable to a rotary part, a pair of gripping members connectible to a second Arotary part and disposed on opposite sides of the plate, one of the members having a plurality of spaced projections circumferentially arranged around the face thereof and the other member constituting a floating plate movable axially relative to the other member, and springs for maintaining the driving engagement of the members and friction plate, of unloading mechanism forreleasing said engagement comprising pins journaled on the floating plate, a bell crank lever mounted onv each pin, means for actuating one `arm of each adapted to fulcrum against the associated projection to thereby disengage `the floating plate and moving to an over-center position relative to the cooperating projection to lock the clutch in disengaged position, means formed on the floating plate; for limiting the releasing movement of the first-named lever arms to maintain said overcenter position, the radius of each lever pivot being greater than the radius of the associated projection to thereby provide for a quick releasing movement of the levers to free the floating plate for return to vgripping position, and means for adjusting the position of each block as the clutch wears, the adjusting means passing throug the pins to secure the levers thereto.

| WILLIAM J. PEARMAIN. 

